Kenny MacAskill, who served as Justice Secretary in Alex Salmond's cabinet and was just elected as MP for East Lothian, said the success of a drive by Nicola Sturgeon for a second vote on independence in 2020 was "slim", while former SNP deputy leader Jim Sillars, said Ms Sturgeon was leading independence activists "up the garden path".
Mr MacAskill, who left the Scottish cabinet when Nicola Sturgeon became First Minister in 2014, also called for a new alliance with the Labour Party to “build on the anger” felt in Scotland towards Boris Johnson’s new Tory government.
Today's Herald reported that a piece to be published in the forthcoming Scottish Left Review, sees Mr MacAskill encourage Scottish elected politicians and parties to work together, the goal of which should be "a united demand for Scottish independence, or at least unity on the right of the Scottish people to choose their own future.
“It can be the basis to show the world that it’s not one party, but the people who are demanding it,” he writes.
However he said the chances of a second referendum this year were "slim - indeed, more likely nil.”
In the same issue, former SNP deputy leader Jim Sillars writes: “Everyone with any political nous knows that Nicola’s demand for indyref2 in 2020 is play acting to up the grudge feeling when Johnson says no.
“How the activist gallery to which she is playing don’t see they are being led up the garden path beats me.”
He also accused Ms Sturgeon of undermining her claim to have a mandate for a second vote by muddying her campaign messages in the election, moving away from independence to focus on Brexit.
“Nicola Sturgeon never went for an unambiguous vote for independence, using the softest language on indyref2 with a formula that it was right for Scots to make a decision about our future," he writes. "Something difficult for any reasonable person to disagree.
“Then, she changed tack, and made the last lap all about stopping Boris and Brexit. So another election goes by and the SNP sought ‘remainer’ Unionist votes, thus undermining the claim to have a mandate for indyref2.
“Another chance missed to build the independence vote.”
Mr Sillars said that Boris Johnson's refusal for a referendum would leave Scotland “stuck”, and the SNP with more MPs, but who would only “demonstrate their impotence” in London.
Tory MSP Maurice Golden said: “The arrival of a new year doesn’t seem to have eased the tensions at the top of the SNP. If anything the divisions are growing deeper. “And as the party of government in Scotland continues to tear itself apart over constitutional issues, our schools, hospitals and infrastructure suffer.”
Mr MacAskill also said there should be protest marches to demand a second referendum and also suggested peaceful civil disobedience of the sort seen against the Poll Tax in the 1980s.
Calling for “unity on the Left”, he writes: “We face an attack upon the social infrastructure of our country. The welfare state and even the NHS are in Johnson’s sights, whatever pledges he has made. Far from rolling back the gig economy, it’s likely to morph into something larger.
“Bringing Scottish elected politicians and parties together is essential. Whether that’s a constitutional convention as before, a convocation of elected parliamentarians from both chambers or a wider gathering can be discussed and agreed.
“Whoever calls it and whoever attends, it must be held soon. Building on the anger that currently exists rather than allowing despondency to settle in is required.
“It must address the high-level constitutional challenge and seek to create unity either behind independence or just the Scottish people’s right to choose their own future. It can be the basis to show the world that it’s not one party but the people who are demanding it.”
His and Mr Sillars' comments were welcomed by Scotland in Union, which said they proved the First Minister should drop her demand for a Section 30 Order - the power required to hold a referendum.
Pamela Nash, chief executive of the pro-UK organisation, said: “Even senior SNP figures admit there won’t be a divisive second referendum this year. But Nicola Sturgeon is obsessed about another contest at the expense of our public services.
“Every minute and every pound spent on pursuing an unwanted second referendum is time and money taken away from fixing our public services and improving our economy and the quality of life of Scots. Scotland deserves better.
“It’s time for Nicola Sturgeon to drop her demand for a Section 30 order and focus on doing her job.”
A spokesperson for the SNP said: “In line with repeated election mandates received from the people of Scotland, a referendum should be held before the end of 2020 with the precise timing a matter for the Scottish Parliament.
“Scotland’s future should be in Scotland’s hands – not those of Boris Johnson.”